A healthy lifestyle at 75 gives a person the same chance of living for a further 10 years as someone a decade younger who smokes and drinks, a Swiss study has found.

For the first time, researchers have calculated a pensioner's chances of surviving for another decade, based on habits such as smoking, drinking, exercise and fruit consumption.

The study of more than 16,000 people found that men aged 75 who smoked, regularly drank alcohol, led inactive lifestyles and ate little fruit had just a 35pc chance of being alive a decade later.

Others of the same age who did not smoke, took exercise, ate fruit and had moderate or no alcohol consumption had a 67pc chance of living a decade – the same figure for men 10 years younger with unhealthy lifestyles.

Among women, 75-year-olds with healthy lifestyles had a 74pc chance of being alive a decade later. The projection was only slightly lower for women 10 years younger who smoked, drank a lot, rarely ate fruit and took little exercise.

Lifestyles

The calculator, from a team at the University of Zurich, allows men and women aged 65 and 75 to estimate their chances of living for a decade.

Alcohol intake was classed as high if women reported drinking at least two units of alcohol a day (175ml wine) and if men drank at least four units (less than two pints of lager) a day. The study found that lifestyles had little impact on death rates among those aged between 45 and 55.

Smoking had the greatest impact on life expectancy, increasing the risk of premature death by 57pc.

Each of the other three factors – alcohol, diet and exercise – increased risk by around 15pc each.